This invention relates in general to a system for measuring a gas sealed within an insulating glass assembly, and more particularly a gas concentration meter and method used for measuring the concentration of a gas within a sealed cavity or window assembly and a means of providing access to the sealed cavity.
Due to the high cost of heating and cooling in most building structures, high efficiency and energy saving means are desirable for fenestration systems such as windows, doors, curtain walls, skylights or the like. Typically such systems include sealed insulating glass units filled with an inert gas. Traditionally these insulating systems have had an insulating air space or vacuum between the panels, which recently included a gas such as Argon to improve thermal performance. The inclusion of the gas is to provide additional insulation or resistance to thermal conductivity. Argon is the gas predominantly used due to its high benefit/cost ratio.
Over time the gas may escape or dissipate due to faulty seals of the like, which negates the beneficial effects of the insulating windows and results in increased energy costs. Due to the nature of the gases involved as described above, it is difficult to determine how much of the gas has escaped, and therefore what concentration of gas is left in the glass assembly. Furthermore if the gas concentration is found lower than the promised or the pre-selected level, the sealed insulating glass unit cannot generally be replenished without destroying the frame or seal of the fenestration system.
Several methods for measuring gas concentration in insulating glass units do exist today. However, such methods require sampling and analysis of the gas in the insulating glass unit""s cavity. The use of such methods is severely limited, as the sampling of gas within the cavity cannot be performed on an insulating glass unit once it is glazed in place. Once the insulating unit is glazed in place, the edge seal becomes inaccessible. Any attempt to carry out sampling of the insulating glass unit is made at the risk of damaging the edge seal, which will promote insulating unit failure in a very short period of time.
Presently, buyers of gas-filled sealed units can only rely on the supplier""s assuring words that the supplied units do contain insulating gas within the insulating cavity. As the fill gas is colorless and odorless, and inaccessible, there is no means of verifying such claims. Currently, insulating gas unit manufacturers may be certified that they comply with National Standards regarding gas concentration test requirements. Due to the lack of a more practical test method, the only reliable method that has been adopted by the Standard is gas chromatography. This method, however, requires sampling of gas in inaccessible cavity, and use of highly specialized analytical equipment and technicians to operate under strict laboratory conditions.
Current method of determining gas concentration involves measuring of Oxygen concentration in the cavity as it relates to presence of air. Other methods (under development) may be used to measure the concentration of a gas within the sealed units consist of applying a high voltage electrical current in the range of 10,000 to 20,000 volts across the glazing cavity (i.e. across the outside surfaces of the spaced glass).
Therefore, while the existing methods of determining gas concentration in insulating glass units can be used for laboratory research and testing of non-glazed sealed units, these methods cannot be employed effectively for routine quality control and field-testing purposes.
Furthermore, the ability to access and measure the level of gas within the glass assembly would allow the installer to add more gas when required and therefore maintain the insulating benefits of the glass.
Prior art glass assemblies have been devised to try and address the aforenoted problems. For example, U.S. Pat. No. 5,299,399 which issued on Apr. 5, 1994 to the inventors Bruce A. Baier et al. and was assigned to Pella Corporation of Pella, Iowa. This patent relates to a dual glazing window that has a removable glazing panel, which includes a breather system that connects the air chamber between the glazing panels with the outside ambient air by routing an outwardly facing channel into the window rail.
U.S. Pat. No. 2,880,475 issued on Apr. 7, 1959, and relates to a double glazed window unit suitable for use in a window, in which the space between the glass panels is evacuated to provide good insulating qualities and to prevent the formation of condensation due to temperature differences between the inner and outer panels.
U.S. Pat. No. 2,125,372 was issued on Aug. 2, 1938 and relates to a fitting for a glass sheet having a perforation and comprises of a metal connection plug having a threaded passage, which fits into the perforation for sealing the glass sheet.
U.S. Pat. No. 1,336,211 was issued on Apr. 6, 1920 to Henry Duffy of Longmont, Colorado and relates to an exteriorly threaded plug having a central port and a lateral passage with a valve seated in the passage, and having a transverse port.
Thus a gas concentration meter used for measuring the concentration of a gas within a sealed insulating unit or glass assembly and method thereof is desirable. Furthermore a non-obtrusive means of providing access to the insulating cavity to measure and/or replenish a gas within the cavity would be beneficial.
An object of one aspect of the present invention is to provide a gas concentration meter and improved insulating glass assembly and a method thereof.
In accordance with one aspect of the present invention there is provided a system for measuring the concentration of a gas within a sealed insulating cavity having an access means for communicating with the sealed insulating cavity, a probing means for insertion through the access means to the gas and having the ability to sense the concentration of the gas, and a measuring means for measuring and displaying the concentration of the gas through the probing means.
Conveniently, the access means is further defined as an access port assembly having a connecting means through the glazing spacer block and a stopping means.
Preferrably, the connecting means spacer block may be defined as a connecting tube being integrally molded to a spacer block for insertion between the glass panes of the insulating unit.
In accordance with another aspect of the present invention, the probing means may be further defined as a pair of flexible electrodes which may be separated by a predetermined distance to form a gap.
In accordance with still another aspect of the invention, the measuring means may be defined as a meter having electronic circuitry to excite, control, monitor the excitation level, relate the excitation level to gas concentration through calibration means, and indicate or display the concentration level.
Another object of the present invention is to provide an improved method for measuring the concentration of a gas in a gas filled sealed insulating glazing assembly comprising of at least two spaced glass panes wherein the method comprises the following steps:
a) inserting a probing means through an access means for communication with the cavity of the gas filled insulating unit;
b) or placement of permanent probing means into the glazing cavity through the edge seal of the insulating unit;
c) or placement of permanent probing means in a gas sampling device such as a syringe or any other sampling container;
d) sensing the concentration of the gas with the probing means; and relaying the concentration of the gas to a measuring means for measuring the concentration of the gas.
Advantages of the present invention are:
a) ability to measure actual gas concentration on site or at the plant,
b) ability to pressure equalize the glazing cavity in order to eliminate glass distortion or breakage, and
c) ability to re-fill the insulated units with gas if gas-filling was deemed inadequate, thereby reducing the number of gas-filled units that have to be replaced.